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Ron T, Leon A, Kafri A, Ashraf A, Na J, Babu A, Banerjee R, Brookbank H, Muddaluri SR, Little KJ, Aghion E, Pixley S. Nerve Regeneration with a Scaffold Incorporating an Absorbable Zinc-2% Iron Alloy Filament to Improve Axonal Guidance. Pharmaceutics 2023; 15:2595. [PMID: 38004574 PMCID: PMC10674795 DOI: 10.3390/pharmaceutics15112595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/26/2023] Open
Abstract
Peripheral nerve damage that results in lost segments requires surgery, but currently available hollow scaffolds have limitations that could be overcome by adding internal guidance support. A novel solution is to use filaments of absorbable metals to supply physical support and guidance for nerve regeneration that then safely disappear from the body. Previously, we showed that thin filaments of magnesium metal (Mg) would support nerve regeneration. Here, we tested another absorbable metal, zinc (Zn), using a proprietary zinc alloy with 2% iron (Zn-2%Fe) that was designed to overcome the limitations of both Mg and pure Zn metal. Non-critical-sized gaps in adult rat sciatic nerves were repaired with silicone conduits plus single filaments of Zn-2%Fe, Mg, or no metal, with autografts as controls. After seventeen weeks, all groups showed equal recovery of function and axonal density at the distal end of the conduit. The Zn alloy group showed some improvements in early rat health and recovery of function. The alloy had a greater local accumulation of degradation products and inflammatory cells than Mg; however, both metals had an equally thin capsule (no difference in tissue irritation) and no toxicity or inflammation in neighboring nerve tissues. Therefore, Zn-2%Fe, like Mg, is biocompatible and has great potential for use in nervous tissue regeneration and repair.
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Affiliation(s)
- Tomer Ron
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Avi Leon
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Alon Kafri
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
- Nuclear Research Centre-Negev, Beer-Sheva 84190, Israel
| | - Ahmed Ashraf
- College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - John Na
- College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Ashvin Babu
- School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Runima Banerjee
- College of Engineering & Applied Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Hunter Brookbank
- College of Arts & Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | | | - Kevin J. Little
- Department of Orthopedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
- Pediatric Hand & Upper Extremity Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Eli Aghion
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Sarah Pixley
- Department of Pharmacology & Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
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Tatu R, White LG, Yun Y, Hopkins T, An X, Ashraf A, Little KJ, Hershcovitch M, Hom DB, Pixley S. Effects of Altering Magnesium Metal Surfaces on Degradation In Vitro and In Vivo during Peripheral Nerve Regeneration. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1195. [PMID: 36770202 PMCID: PMC9920421 DOI: 10.3390/ma16031195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
In vivo use of biodegradable magnesium (Mg) metal can be plagued by too rapid a degradation rate that removes metal support before physiological function is repaired. To advance the use of Mg biomedical implants, the degradation rate may need to be adjusted. We previously demonstrated that pure Mg filaments used in a nerve repair scaffold were compatible with regenerating peripheral nerve tissues, reduced inflammation, and improved axonal numbers across a short-but not long-gap in sciatic nerves in rats. To determine if the repair of longer gaps would be improved by a slower Mg degradation rate, we tested, in vitro and in vivo, the effects of Mg filament polishing followed by anodization using plasma electrolytic oxidation (PEO) with non-toxic electrolytes. Polishing removed oxidation products from the surface of as-received (unpolished) filaments, exposed more Mg on the surface, produced a smoother surface, slowed in vitro Mg degradation over four weeks after immersion in a physiological solution, and improved attachment of cultured epithelial cells. In vivo, treated Mg filaments were used to repair longer (15 mm) injury gaps in adult rat sciatic nerves after placement inside hollow poly (caprolactone) nerve conduits. The addition of single Mg or control titanium filaments was compared to empty conduits (negative control) and isografts (nerves from donor rats, positive control). After six weeks in vivo, live animal imaging with micro computed tomography (micro-CT) showed that Mg metal degradation rates were slowed by polishing vs. as-received Mg, but not by anodization, which introduced greater variability. After 14 weeks in vivo, functional return was seen only with isograft controls. However, within Mg filament groups, the amount of axonal growth across the injury site was improved with slower Mg degradation rates. Thus, anodization slowed degradation in vitro but not in vivo, and degradation rates do affect nerve regeneration.
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Affiliation(s)
- Rigwed Tatu
- Department of Pharmacology & Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
- PSN Labs (Plastics Services Network), Erie, PA 16510, USA
| | - Leon G. White
- Department of Mechanical Engineering, Department of Bioengineering, North Carolina Agricultural & Technical State University, Greensboro, NC 27411, USA
- Northrop Grumman, Baltimore, MD 21240, USA
| | - Yeoheung Yun
- Department of Mechanical Engineering, Department of Bioengineering, North Carolina Agricultural & Technical State University, Greensboro, NC 27411, USA
| | - Tracy Hopkins
- Department of Pharmacology & Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Xiaoxian An
- Division of Pharmaceutical Sciences, James L. Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Ahmed Ashraf
- Department of Pharmacology & Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Kevin J. Little
- College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - Meir Hershcovitch
- College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
| | - David B. Hom
- Department of Pharmacology & Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
- Head & Neck Surgery, San Diego Medical Center, University of California, San Diego, CA 92103, USA
| | - Sarah Pixley
- Department of Pharmacology & Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA
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Abstract
Silk is a functional protein biomaterial produced by a variety of insects like flies, silkworms, scorpions, spiders, and mites. Silk synthesized by silkworms is extensively studied for its applications in tissue engineering and wound healing. Silk is undoubtedly a natural biocompatible material with humans and has its role in medical treatments from ancient times. The silk worm protein comprises two types of proteins namely fibroin and sericin. Silk fibroin makes up approximately 70% of cocoon weight and has wide applications in textiles and in all biomedical applications owing to its biocompatible, nontoxic, biodegradable, less immunogenic, and noncarcinogenic nature. It possesses outstanding toughness and mechanical strength, while silk sericin possesses high defensive ability against ultraviolet light and oxidation. Silk fibroin has been known to induce wound healing by increasing cell proliferation and growth and migrating various types of cells which are involved in different stages of wound healing process. With several silk varieties like silk worm fibroin, silk sericin, recombinant silk materials, and native spider silk have been investigated for its wound healing applications over the last several decades. With an objective of harnessing the silk regenerative properties, plentiful strategies have been studied and applied to develop bioartificial skin grafts and bioactive wound dressings in recent times. This review gives a detailed insight into the structure, general properties, fibroin structure-properties relationship, and biomedical applications of silk fibroin.
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Liu FD, Duan HM, Hao F, Zhao W, Gao YD, Hao P, Yang ZY, Li XG. Biomimetic chitosan scaffolds with long-term controlled release of nerve growth factor repairs 20-mm-long sciatic nerve defects in rats. Neural Regen Res 2021; 17:1146-1155. [PMID: 34558544 PMCID: PMC8552858 DOI: 10.4103/1673-5374.324860] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although autogenous nerve transplantation is the gold standard for treating peripheral nerve defects of considerable length, it still has some shortcomings, such as insufficient donors and secondary injury. Composite chitosan scaffolds loaded with controlled release of nerve growth factor can promote neuronal survival and axonal regeneration after short-segment sciatic nerve defects. However, the effects on extended nerve defects remain poorly understood. In this study, we used chitosan scaffolds loaded with nerve growth factor for 8 weeks to repair long-segment (20 mm) sciatic nerve defects in adult rats. The results showed that treatment markedly promoted the recovery of motor and sensory functions. The regenerated sciatic nerve not only reconnected with neurons but neural circuits with the central nervous system were also reconstructed. In addition, the regenerated sciatic nerve reconnected the motor endplate with the target muscle. Therefore, this novel biomimetic scaffold can promote the regeneration of extended sciatic nerve defects and reconstruct functional circuits. This provides a promising method for the clinical treatment of extended peripheral nerve injury. This study was approved by the Animal Ethics Committee of Capital Medical University, China (approval No. AEEI-2017-033) on March 21, 2017.
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Affiliation(s)
- Fa-Dong Liu
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Hong-Mei Duan
- Department of Neurobiology, Capital Medical University, Beijing, China
| | - Fei Hao
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Wen Zhao
- Department of Neurobiology, Capital Medical University, Beijing, China
| | - Yu-Dan Gao
- Department of Neurobiology, Capital Medical University, Beijing, China
| | - Peng Hao
- Department of Neurobiology, Capital Medical University, Beijing, China
| | - Zhao-Yang Yang
- Department of Neurobiology, Capital Medical University; Beijing International Cooperation Bases for Science and Technology on Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
| | - Xiao-Guang Li
- Beijing Key Laboratory for Biomaterials and Neural Regeneration, School of Biological Science and Medical Engineering, Beihang University; Department of Neurobiology, Capital Medical University; Beijing International Cooperation Bases for Science and Technology on Biomaterials and Neural Regeneration, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
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Rodríguez-Sánchez DN, Pinto GBA, Cartarozzi LP, de Oliveira ALR, Bovolato ALC, de Carvalho M, da Silva JVL, Dernowsek JDA, Golim M, Barraviera B, Ferreira RS, Deffune E, Bertanha M, Amorim RM. 3D-printed nerve guidance conduits multi-functionalized with canine multipotent mesenchymal stromal cells promote neuroregeneration after sciatic nerve injury in rats. Stem Cell Res Ther 2021; 12:303. [PMID: 34051869 PMCID: PMC8164252 DOI: 10.1186/s13287-021-02315-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/29/2021] [Indexed: 01/09/2023] Open
Abstract
Background Nerve injuries are debilitating, leading to long-term motor deficits. Remyelination and axonal growth are supported and enhanced by growth factor and cytokines. Combination of nerve guidance conduits (NGCs) with adipose-tissue-derived multipotent mesenchymal stromal cells (AdMSCs) has been performing promising strategy for nerve regeneration. Methods 3D-printed polycaprolactone (PCL)-NGCs were fabricated. Wistar rats subjected to critical sciatic nerve damage (12-mm gap) were divided into sham, autograft, PCL (empty NGC), and PCL + MSCs (NGC multi-functionalized with 106 canine AdMSCs embedded in heterologous fibrin biopolymer) groups. In vitro, the cells were characterized and directly stimulated with interferon-gamma to evaluate their neuroregeneration potential. In vivo, the sciatic and tibial functional indices were evaluated for 12 weeks. Gait analysis and nerve conduction velocity were analyzed after 8 and 12 weeks. Morphometric analysis was performed after 8 and 12 weeks following lesion development. Real-time PCR was performed to evaluate the neurotrophic factors BDNF, GDNF, and HGF, and the cytokine and IL-10. Immunohistochemical analysis for the p75NTR neurotrophic receptor, S100, and neurofilament was performed with the sciatic nerve. Results The inflammatory environment in vitro have increased the expression of neurotrophins BDNF, GDNF, HGF, and IL-10 in canine AdMSCs. Nerve guidance conduits multi-functionalized with canine AdMSCs embedded in HFB improved functional motor and electrophysiological recovery compared with PCL group after 12 weeks. However, the results were not significantly different than those obtained using autografts. These findings were associated with a shift in the regeneration process towards the formation of myelinated fibers. Increased immunostaining of BDNF, GDNF, and growth factor receptor p75NTR was associated with the upregulation of BDNF, GDNF, and HGF in the spinal cord of the PCL + MSCs group. A trend demonstrating higher reactivity of Schwann cells and axonal branching in the sciatic nerve was observed, and canine AdMSCs were engrafted at 30 days following repair. Conclusions 3D-printed NGCs multi-functionalized with canine AdMSCs embedded in heterologous fibrin biopolymer as cell scaffold exerted neuroregenerative effects. Our multimodal approach supports the trophic microenvironment, resulting in a pro-regenerative state after critical sciatic nerve injury in rats.
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Affiliation(s)
- Diego Noé Rodríguez-Sánchez
- Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Giovana Boff Araujo Pinto
- Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Luciana Politti Cartarozzi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | | | - Ana Livia Carvalho Bovolato
- Blood Transfusion Center, Cell Engineering Laboratory, Botucatu Medical School, São Paulo State University, Botucatu, SP, Brazil
| | - Marcio de Carvalho
- Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Jorge Vicente Lopes da Silva
- Renato Archer Information Technology Center (CTI), Three-dimensional Technologies Research Group, Campinas, SP, Brazil
| | - Janaina de Andréa Dernowsek
- Renato Archer Information Technology Center (CTI), Three-dimensional Technologies Research Group, Campinas, SP, Brazil
| | - Marjorie Golim
- Hemocenter division of Botucatu Medical School, São Paulo State University, Botucatu, SP, Brazil
| | - Benedito Barraviera
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Rui Seabra Ferreira
- Center for the Study of Venoms and Venomous Animals (CEVAP), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Elenice Deffune
- Blood Transfusion Center, Cell Engineering Laboratory, Botucatu Medical School, São Paulo State University, Botucatu, SP, Brazil
| | - Mathues Bertanha
- Blood Transfusion Center, Cell Engineering Laboratory, Botucatu Medical School, São Paulo State University, Botucatu, SP, Brazil
| | - Rogério Martins Amorim
- Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, SP, Brazil.
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Doostmohammadi M, Forootanfar H, Ramakrishna S. Regenerative medicine and drug delivery: Progress via electrospun biomaterials. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 109:110521. [PMID: 32228899 DOI: 10.1016/j.msec.2019.110521] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 12/01/2019] [Accepted: 12/02/2019] [Indexed: 02/07/2023]
Abstract
Worldwide research on electrospinning enabled it as a versatile technique for producing nanofibers with specified physio-chemical characteristics suitable for diverse biomedical applications. In the case of tissue engineering and regenerative medicine, the nanofiber scaffolds' characteristics are custom designed based on the cells and tissues specific needs. This fabrication technique is also innovated for the production of nanofibers with special micro-structure and secondary structure characteristics such as porous fibers, hollow structure, and core- sheath structure. This review attempts to critically and succinctly capture the vast number of developments reported in the literature over the past two decades. We then discuss their applications as scaffolds for induction of cells growth and differentiation or as architecture for being used as graft for tissue engineering. The special nanofibers designed for improving regeneration of several tissues including heart, bone, central nerve system, spinal cord, skin and ocular tissue are introduced. We also discuss the potential of the electrospinning in drug delivery applications, which is a critical factor for cell culture, tissue formation and wound healing applications.
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Affiliation(s)
- Mohsen Doostmohammadi
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Hamid Forootanfar
- Pharmaceutical Sciences and Cosmetic Products Research Center, Kerman University of Medical Sciences, Kerman, Iran; Herbal and Traditional Medicines Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Seeram Ramakrishna
- Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
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Wang M, Li J, Li W, Du Z, Qin S. Preparation and characterization of novel poly (vinyl alcohol)/collagen double-network hydrogels. Int J Biol Macromol 2018; 118:41-48. [DOI: 10.1016/j.ijbiomac.2018.05.200] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/08/2018] [Accepted: 05/26/2018] [Indexed: 10/14/2022]
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McGrath AM, Brohlin M, Wiberg R, Kingham PJ, Novikov LN, Wiberg M, Novikova LN. Long-Term Effects of Fibrin Conduit with Human Mesenchymal Stem Cells and Immunosuppression after Peripheral Nerve Repair in a Xenogenic Model. CELL MEDICINE 2018; 10:2155179018760327. [PMID: 32634185 PMCID: PMC6172997 DOI: 10.1177/2155179018760327] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 01/07/2018] [Accepted: 01/12/2018] [Indexed: 12/22/2022]
Abstract
Introduction: Previously we showed that a fibrin glue conduit with human mesenchymal stem cells
(hMSCs) and cyclosporine A (CsA) enhanced early nerve regeneration. In this study long
term effects of this conduit are investigated. Methods: In a rat model, the sciatic nerve was repaired with fibrin conduit containing fibrin
matrix, fibrin conduit containing fibrin matrix with CsA treatment and fibrin conduit
containing fibrin matrix with hMSCs and CsA treatment, and also with nerve graft as
control. Results: At 12 weeks 34% of motoneurons of the control group regenerated axons through the
fibrin conduit. CsA treatment alone or with hMSCs resulted in axon regeneration of 67%
and 64% motoneurons respectively. The gastrocnemius muscle weight was reduced in the
conduit with fibrin matrix. The treatment with CsA or CsA with hMSCs induced recovery of
the muscle weight and size of fast type fibers towards the levels of the nerve graft
group. Discussion: The transplantation of hMSCs for peripheral nerve injury should be optimized to
demonstrate their beneficial effects. The CsA may have its own effect on nerve
regeneration.
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Affiliation(s)
- Aleksandra M McGrath
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science, Section for Hand and Plastic Surgery, Norrland's University Hospital, Umeå, Sweden
| | - Maria Brohlin
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.,Department of Clinical Microbiology, Infection and Immunology, Umeå University, Umeå, Sweden
| | - Rebecca Wiberg
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science, Section for Hand and Plastic Surgery, Norrland's University Hospital, Umeå, Sweden
| | - Paul J Kingham
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden
| | - Lev N Novikov
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden
| | - Mikael Wiberg
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden.,Department of Surgical and Perioperative Science, Section for Hand and Plastic Surgery, Norrland's University Hospital, Umeå, Sweden
| | - Liudmila N Novikova
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, Umeå, Sweden
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Petcu EB, Midha R, McColl E, Popa-Wagner A, Chirila TV, Dalton PD. 3D printing strategies for peripheral nerve regeneration. Biofabrication 2018; 10:032001. [DOI: 10.1088/1758-5090/aaaf50] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Repair of nerve injury by implanting prostheses obtained from isogenic acellular nerve segments. Rev Esp Cir Ortop Traumatol (Engl Ed) 2017. [DOI: 10.1016/j.recote.2017.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Hopkins TM, Little KJ, Vennemeyer JJ, Triozzi JL, Turgeon MK, Heilman AM, Minteer D, Marra K, Hom DB, Pixley SK. Short and long gap peripheral nerve repair with magnesium metal filaments. J Biomed Mater Res A 2017; 105:3148-3158. [PMID: 28782170 DOI: 10.1002/jbm.a.36176] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 06/28/2017] [Accepted: 08/01/2017] [Indexed: 11/06/2022]
Abstract
A current clinical challenge is to replace autografts for repair of injury gaps in peripheral nerves, which can occur due to trauma or surgical interruption. Biodegradable metallic magnesium filaments, placed inside hollow nerve conduits, could support nerve repair by providing contact guidance support for axonal regeneration. This was tested by repairing sciatic nerves of adult rats with single magnesium filaments placed inside poly(caprolactone) nerve conduits. Controls were empty conduits, conduits containing titanium filaments and/or isografts from donor rats. With a nerve gap of 6 mm and 6 weeks post-repair, magnesium filaments had partially resorbed. Regenerating cells had attached to the filaments and axons were observed in distal stumps in all animals. Axon parameters were improved with magnesium compared to conduits alone or conduits with single titanium filaments. With a longer gap of 15 mm and 16 weeks post-repair, functional parameters were improved with isografts, but not with magnesium filaments or empty conduits. Magnesium filaments were completely resorbed and no evidence of scarring was seen. While axon outgrowth was not improved with the longer gap, histological measures of the tissues were improved with magnesium compared to empty conduits. Therefore, the use of magnesium filaments is promising because they are biocompatible and improve aspects of nerve regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3148-3158, 2017.
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Affiliation(s)
- Tracy M Hopkins
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
| | - Kevin J Little
- Division of Pediatric Orthopaedics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, Ohio 45229
| | - John J Vennemeyer
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
| | - Jefferson L Triozzi
- Student Affairs, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
| | - Michael K Turgeon
- Student Affairs, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
| | - Alexander M Heilman
- Student Affairs, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
| | - D Minteer
- Department of Plastic Surgery, University of Pittsburgh, 3380 Boulevard of the Allies, Suite 138, Pittsburgh, Pennsylvania 15213
| | - K Marra
- Departments of Plastic Surgery and Bioengineering, 1655E BST, University of Pittsburgh, 200 Lothrop St., Pittsburgh, Pennsylvania 15261
| | - David B Hom
- Division of Facial Plastic & Reconstructive Surgery, Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
| | - Sarah K Pixley
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267
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García-Medrano B, Mesuro Domínguez N, Simón Pérez C, Garrosa García M, Gayoso Del Villar S, Mayo Íscar A, Gayoso Rodríguez MJ, Martín Ferrero MA. Repair of nerve injury by implanting prostheses obtained from isogenic acellular nerve segments. Rev Esp Cir Ortop Traumatol (Engl Ed) 2017; 61:359-366. [PMID: 28760548 DOI: 10.1016/j.recot.2017.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 05/22/2017] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
INTRODUCTION When a nerve section with a significant gap occurs, it is necessary to use a prosthesis to suture it. To date an autologous nerve segment graft appears to be the best treatment; but it has several important disadvantages. Our goal is to study the effectiveness of an isogenic acellular nerve prosthesis comparing a simple suture with tubulisation. MATERIAL AND METHOD Four groups of Wistar rats were used. The animals in Group 0 served as donors of nerve segments to graft. Group 1 received the implant with an end-to-end suture. In group 2, the implant was sutured inside an ɛ-caprolactone tube. Group 3 received it in a polylactic-co-glycolic acid tube. We evaluated the motor function (sciatic index and step test in motion), and the regeneration length by histological study of regeneration, after a maximum of 3 weeks. RESULTS Regeneration was uneven in the three groups. In all groups, there were implants with regenerated nerve fibres at the maximum studied length (15mm) and others where regeneration was scarce. The mean regeneration length was greater in the direct end-to-end suture group (G1), although the regeneration speed was similar in the three groups. Group 1 showed the highest percentage of regeneration, but the variability of results prevents this difference reaching statistical significance. We found no significant differences between the two groups with polymer tubes. CONCLUSION For the implantation of isogenic acellular nerve prosthesis, under our experimental conditions, the direct end-to-end suture was more effective than when it isprotected with biopolymer tubes.
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Affiliation(s)
- B García-Medrano
- Servicio de Cirugía Ortopédica y Traumatología, Hospital Clínico Universitario de Valladolid, Valladolid, España.
| | - N Mesuro Domínguez
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Valladolid, Valladolid, España
| | - Cl Simón Pérez
- Servicio de Cirugía Ortopédica y Traumatología, Hospital Clínico Universitario de Valladolid, Valladolid, España
| | - M Garrosa García
- Estadística e Investigación Operativa, Universidad de Medicina de Valladolid, Valladolid, España
| | - S Gayoso Del Villar
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Valladolid, Valladolid, España
| | - A Mayo Íscar
- Estadística e Investigación Operativa, Universidad de Medicina de Valladolid, Valladolid, España
| | - M J Gayoso Rodríguez
- Departamento de Biología Celular, Facultad de Medicina, Universidad de Valladolid, Valladolid, España
| | - M A Martín Ferrero
- Servicio de Cirugía Ortopédica y Traumatología, Hospital Clínico Universitario de Valladolid, Valladolid, España
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Kohn-Polster C, Bhatnagar D, Woloszyn DJ, Richtmyer M, Starke A, Springwald AH, Franz S, Schulz-Siegmund M, Kaplan HM, Kohn J, Hacker MC. Dual-Component Gelatinous Peptide/Reactive Oligomer Formulations as Conduit Material and Luminal Filler for Peripheral Nerve Regeneration. Int J Mol Sci 2017; 18:E1104. [PMID: 28531139 PMCID: PMC5455012 DOI: 10.3390/ijms18051104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/09/2017] [Accepted: 05/17/2017] [Indexed: 02/01/2023] Open
Abstract
Toward the next generation of nerve guidance conduits (NGCs), novel biomaterials and functionalization concepts are required to address clinical demands in peripheral nerve regeneration (PNR). As a biological polymer with bioactive motifs, gelatinous peptides are promising building blocks. In combination with an anhydride-containing oligomer, a dual-component hydrogel system (cGEL) was established. First, hollow cGEL tubes were fabricated by a continuous dosing and templating process. Conduits were characterized concerning their mechanical strength, in vitro and in vivo degradation and biocompatibility. Second, cGEL was reformulated as injectable shear thinning filler for established NGCs, here tyrosine-derived polycarbonate-based braided conduits. Thereby, the formulation contained the small molecule LM11A-31. The biofunctionalized cGEL filler was assessed regarding building block integration, mechanical properties, in vitro cytotoxicity, and growth permissive effects on human adipose tissue-derived stem cells. A positive in vitro evaluation motivated further application of the filler material in a sciatic nerve defect. Compared to the empty conduit and pristine cGEL, the functionalization performed superior, though the autologous nerve graft remains the gold standard. In conclusion, LM11A-31 functionalized cGEL filler with extracellular matrix (ECM)-like characteristics and specific biochemical cues holds great potential to support PNR.
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Affiliation(s)
- Caroline Kohn-Polster
- Institute of Pharmacy, Pharmaceutical Technology, Leipzig University, 04317 Leipzig, Germany.
- Collaborative Research Center (SFB-TR67), Matrixengineering Leipzig and Dresden, Germany.
| | - Divya Bhatnagar
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8066, USA.
| | - Derek J Woloszyn
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8066, USA.
- Boston University School of Medicine, Boston University, Boston, MA 02118, USA.
| | - Matthew Richtmyer
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8066, USA.
| | - Annett Starke
- Institute of Pharmacy, Pharmaceutical Technology, Leipzig University, 04317 Leipzig, Germany.
| | - Alexandra H Springwald
- Institute of Pharmacy, Pharmaceutical Technology, Leipzig University, 04317 Leipzig, Germany.
| | - Sandra Franz
- Collaborative Research Center (SFB-TR67), Matrixengineering Leipzig and Dresden, Germany.
- Department of Dermatology, Venereology and Allergology of Medical Faculty of Leipzig University, 04317 Leipzig, Germany.
| | - Michaela Schulz-Siegmund
- Institute of Pharmacy, Pharmaceutical Technology, Leipzig University, 04317 Leipzig, Germany.
- Collaborative Research Center (SFB-TR67), Matrixengineering Leipzig and Dresden, Germany.
| | - Hilton M Kaplan
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8066, USA.
| | - Joachim Kohn
- New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8066, USA.
| | - Michael C Hacker
- Institute of Pharmacy, Pharmaceutical Technology, Leipzig University, 04317 Leipzig, Germany.
- Collaborative Research Center (SFB-TR67), Matrixengineering Leipzig and Dresden, Germany.
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Yannas IV, Tzeranis DS, So PTC. Regeneration of injured skin and peripheral nerves requires control of wound contraction, not scar formation. Wound Repair Regen 2017; 25:177-191. [PMID: 28370669 PMCID: PMC5520812 DOI: 10.1111/wrr.12516] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/24/2017] [Accepted: 02/02/2017] [Indexed: 01/05/2023]
Abstract
We review the mounting evidence that regeneration is induced in wounds in skin and peripheral nerves by a simple modification of the wound healing process. Here, the process of induced regeneration is compared to the other two well-known processes by which wounds close, i.e., contraction and scar formation. Direct evidence supports the hypothesis that the mechanical force of contraction (planar in skin wounds, circumferential in nerve wounds) is the driver guiding the orientation of assemblies of myofibroblasts (MFB) and collagen fibers during scar formation in untreated wounds. We conclude that scar formation depends critically on wound contraction and is, therefore, a healing process secondary to contraction. Wound contraction and regeneration did not coincide during healing in a number of experimental models of spontaneous (untreated) regeneration described in the literature. Furthermore, in other studies in which an efficient contraction-blocker, a collagen scaffold named dermis regeneration template (DRT), and variants of it, were grafted on skin wounds or peripheral nerve wounds, regeneration was systematically observed in the absence of contraction. We conclude that contraction and regeneration are mutually antagonistic processes. A dramatic change in the phenotype of MFB was observed when the contraction-blocking scaffold DRT was used to treat wounds in skin and peripheral nerves. The phenotype change was directly observed as drastic reduction in MFB density, dispersion of MFB assemblies and loss of alignment of the long MFB axes. These observations were explained by the evidence of a surface-biological interaction of MFB with the scaffold, specifically involving binding of MFB integrins α1 β1 and α2 β1 to ligands GFOGER and GLOGER naturally present on the surface of the collagen scaffold. In summary, we show that regeneration of wounded skin and peripheral nerves in the adult mammal can be induced simply by appropriate control of wound contraction, rather than of scar formation.
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Affiliation(s)
- Ioannis V Yannas
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Dimitrios S Tzeranis
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Peter T C So
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
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15
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Trends in the design of nerve guidance channels in peripheral nerve tissue engineering. Prog Neurobiol 2015; 131:87-104. [DOI: 10.1016/j.pneurobio.2015.06.001] [Citation(s) in RCA: 195] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 06/03/2015] [Accepted: 06/09/2015] [Indexed: 01/01/2023]
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Vennemeyer JJ, Hopkins T, Hershcovitch M, Little KD, Hagen MC, Minteer D, Hom DB, Marra K, Pixley SK. Initial observations on using magnesium metal in peripheral nerve repair. J Biomater Appl 2014; 29:1145-54. [PMID: 25281648 DOI: 10.1177/0885328214553135] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biodegradable magnesium metal filaments placed inside biodegradable nerve conduits might provide the physical guidance support needed to improve the rate and extent of regeneration of peripheral nerves across injury gaps. In this study, we examined basic issues of magnesium metal resorption and biocompatibility by repairing sub-critical size gap injuries (6 mm) in one sciatic nerve of 24 adult male Lewis rats. Separated nerve stumps were connected with poly(caprolactone) nerve conduits, with and without magnesium filaments (0.25 mm diameter, 10 mm length), with two different conduit filler substances (saline and keratin hydrogel). At 6 weeks after implantation, magnesium degradation was examined by micro-computed tomography and histological analyses. Magnesium degradation was significantly greater when the conduits were filled with an acidic keratin hydrogel than with saline (p < 0.05). But magnesium filaments in some animals remained intact for 6 weeks. Using histological and immunocytochemical analyses, good biocompatibility of the magnesium implants was observed at 6 weeks, as shown by good development of regenerating nerve mini-fascicles and only mild inflammation in tissues even after complete degradation of the magnesium. Nerve regeneration was not interrupted by complete magnesium degradation. An initial functional evaluation, determination of size recovery of the gastrocnemius muscle, showed a slight improvement due to magnesium with the saline but not the keratin filler, compared with respective control conduits without magnesium. These results suggest that magnesium filament implants have the potential to improve repair of injured peripheral nerve defects in this rodent model.
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Affiliation(s)
- J J Vennemeyer
- Department of Biomedical Engineering, University of Cincinnati, OH, USA
| | - T Hopkins
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH, USA
| | - M Hershcovitch
- Department of Otolaryngology-Head & Neck Surgery, University of Cincinnati, OH, USA
| | - K D Little
- Department of Orthopaedic Surgery, University of Cincinnati, OH, USA
| | - M C Hagen
- Department of Pathology and Laboratory Medicine, University of Cincinnati, OH, USA
| | - D Minteer
- Department of Bioengineering, University of Pittsburgh, PA, USA
| | - D B Hom
- Division of Facial Plastic and Reconstructive Surgery, Department of Otolaryngology-Head & Neck Surgery and Dermatology, University of Cincinnati, OH, USA
| | - K Marra
- Department of Bioengineering and Department of Plastic Surgery, University of Pittsburgh, PA, USA
| | - S K Pixley
- Department of Molecular and Cellular Physiology, University of Cincinnati, OH, USA
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17
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Hodgkinson T, Yuan XF, Bayat A. Electrospun silk fibroin fiber diameter influences in vitro dermal fibroblast behavior and promotes healing of ex vivo wound models. J Tissue Eng 2014; 5:2041731414551661. [PMID: 25383171 PMCID: PMC4221927 DOI: 10.1177/2041731414551661] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 08/22/2014] [Indexed: 01/26/2023] Open
Abstract
Replicating the nanostructured components of extracellular matrix is a target for dermal tissue engineering and regenerative medicine. Electrospinning Bombyx mori silk fibroin (BMSF) allows the production of nano- to microscale fibrous scaffolds. For BMSF electrospun scaffolds to be successful, understanding and optimizing the cellular response to material morphology is essential. Primary human dermal fibroblast response to nine variants of BMSF scaffolds composed of nano- to microscale fibers ranging from ~250 to ~1200 nm was assessed in vitro with regard to cell proliferation, viability, cellular morphology, and gene expression. BMSF support of epithelial migration was then assessed through utilization of a novel ex vivo human skin wound healing model. Scaffolds composed of the smallest diameter fibers, ~250 -300 nm, supported cell proliferation significantly more than fibers with diameters approximately 1 μm (p < 0.001). Cell morphology was observed to depart from a stellate morphology with numerous cell -fiber interactions to an elongated, fiber-aligned morphology with interaction predominately with single fibers. The expressions of extracellular matrix genes, collagen types I and III (p < 0.001), and proliferation markers, proliferating cell nuclear antigen (p < 0.001), increased with decreasing fiber diameter. The re-epithelialization of ex vivo wound models was significantly improved with the addition of BMSF electrospun scaffolds, with migratory keratinocytes incorporated into scaffolds. BMSF scaffolds with nanofibrous architectures enhanced proliferation in comparison to microfibrous scaffolds and provided an effective template for migratory keratinocytes during re-epithelialization. The results may aid in the development of effective BMSF electrospun scaffolds for wound healing applications
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Affiliation(s)
- Tom Hodgkinson
- Plastic & Reconstructive Surgery Research, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK ; School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK
| | - Xue-Feng Yuan
- National Supercomputer Centre in Guangzhou (NSCC-GZ), Research Institute for Application of High Performance Computing, Sun Yat-Sen University, Guangzhou, P.R. China
| | - Ardeshir Bayat
- Plastic & Reconstructive Surgery Research, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
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18
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Yang X, Guo L, Fan Y, Zhang X. Preparation and characterization of macromolecule cross-linked collagen hydrogels for chondrocyte delivery. Int J Biol Macromol 2013; 61:487-93. [PMID: 23916642 DOI: 10.1016/j.ijbiomac.2013.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 07/26/2013] [Accepted: 07/29/2013] [Indexed: 11/16/2022]
Abstract
Collagen hydrogels are widely used in cartilage tissue engineering for their mimicked chondrogenic environment. Due to the rapid degradation nature and weak mechanical property, collagen hydrogels are often cross-linked in application. In this work, collagen hydrogels were soaked into oxidized alginate solution which used as macromolecular cross-linker to prepare the cross-linked hydrogels. Soaking method could retain the self-assemble property of collagen and also bring in a cross-linking network. The compressive modulus and degradation properties of collagen hydrogels were ameliorated after cross-linked, and chondrocytes encapsulated in the cross-linked hydrogels proliferated well and maintained the cell phenotype. This study implied that collagen hydrogels cross-linked by oxidized alginate may have a great potential for application in cartilage tissue engineering.
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Affiliation(s)
- Xiaoqin Yang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China
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19
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Ho CY, Yao CH, Chen WC, Shen WC, Bau DT. Electroacupuncture and Acupuncture Promote the Rat's Transected Median Nerve Regeneration. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2013; 2013:514610. [PMID: 23573131 PMCID: PMC3610348 DOI: 10.1155/2013/514610] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 02/09/2013] [Indexed: 11/26/2022]
Abstract
Background. Acupuncture and electroacupuncture treatments of damaged nerves may aid nerve regeneration related to hindlimb function, but the effects on the forelimb-related median nerve were not known. Methods. A gap was made in the median nerve of each rat by suturing the stumps into silicone rubber tubes. The influences of acupuncture and electroacupuncture treatments on transected median nerve regeneration were evaluated from morphological, electrophysiological, and functional angles. Results. Morphologically, the group receiving acupuncture and electroacupuncture treatments had larger total nerve area and blood vessel number compared with the controls. Electrophysiologically, the group receiving electroacupuncture had significantly larger amplitude and larger area of the evoked muscle action potentials compared with the controls. Functionally, the acupuncture and electroacupuncture treatments enhanced the injured paw's ability to regain its grasping power and resulted in a faster efficiency to a new bilateral balance. Conclusion. Our findings provide multiapproach evidence of the efficacy of acupuncture and electroacupuncture treatments to the regeneration of median nerve. Indeed, acupuncture and electroacupuncture appear to have positive effects on the regeneration processes. This platform is beneficial to further study the clinical application of acupuncture and electroacupuncture alternative treatments on nerve-injured patients.
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Affiliation(s)
- C. Y. Ho
- School of Chinese Medicine, Institute of Chinese Medicine, China Medical University, 404 Yuh-Der Road, Taichung 40447, Taiwan
- Departments of Family Medicine, China Medical University Hospital, 404 Yuh-Der Road, Taichung 40447, Taiwan
| | - C. H. Yao
- School of Chinese Medicine, Institute of Chinese Medicine, China Medical University, 404 Yuh-Der Road, Taichung 40447, Taiwan
- Department of Biomedical Imaging and Radiological Science, China Medical University Hospital, 404 Yuh-Der Road, Taichung 40447, Taiwan
| | - W. C. Chen
- School of Chinese Medicine, Institute of Chinese Medicine, China Medical University, 404 Yuh-Der Road, Taichung 40447, Taiwan
| | - W. C. Shen
- School of Chinese Medicine, Institute of Chinese Medicine, China Medical University, 404 Yuh-Der Road, Taichung 40447, Taiwan
| | - D. T. Bau
- Graduate Institute of Clinical Medical Science, China Medical University, 404 Yuh-Der Road, Taichung 40447, Taiwan
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20
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Gonzalez-Perez F, Udina E, Navarro X. Extracellular matrix components in peripheral nerve regeneration. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 108:257-75. [PMID: 24083438 DOI: 10.1016/b978-0-12-410499-0.00010-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Injured axons of the peripheral nerve are able to regenerate and, eventually, reinnervate target organs. However, functional recovery is usually poor after severe nerve injuries. The switch of Schwann cells to a proliferative state, secretion of trophic factors, and the presence of extracellular matrix (ECM) molecules (such as collagen, laminin, or fibronectin) in the distal stump are key elements to create a permissive environment for axons to grow. In this review, we focus attention on the ECM components and their tropic role in axonal regeneration. These components can also be used as molecular cues to guide the axons through artificial nerve guides in attempts to better mimic the natural environment found in a degenerating nerve. Most used scaffolds tested are based on natural molecules that form the ECM, but use of synthetic polymers and functionalization of hydrogels are bringing new options. Progress in tissue engineering will eventually lead to the design of composite artificial nerve grafts that may replace the use of autologous nerve grafts to sustain regeneration over long gaps.
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Affiliation(s)
- Francisco Gonzalez-Perez
- Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
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21
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Nan J, Hu X, Li H, Zhang X, Piao R. Use of nerve conduits for peripheral nerve injury repair: A Web of Science-based literature analysis. Neural Regen Res 2012; 7:2826-33. [PMID: 25317133 PMCID: PMC4190865 DOI: 10.3969/j.issn.1673-5374.2012.35.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/02/2012] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE: To identify global research trends in the use of nerve conduits for peripheral nerve injury repair. DATA RETRIEVAL: Numerous basic and clinical studies on nerve conduits for peripheral nerve injury repair were performed between 2002–2011. We performed a bibliometric analysis of the institutions, authors, and hot topics in the field, from the Web of Science, using the key words peripheral nerve and conduit or tube. SELECTION CRITERIA: Inclusion criteria: peer-reviewed published articles on nerve conduits for peripheral nerve injury repair, indexed in the Web of Science; original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items. Exclusion criteria: articles requiring manual searching or telephone access; documents not published in the public domain; and several corrected papers. MAIN OUTCOME MEASURES: (a) Annual publication output; (b) publication type; (c) publication by research field; (d) publication by journal; (e) publication by funding agency; (f) publication by author; (g) publication by country and institution; (h) publications by institution in China; (i) most-cited papers. RESULTS: A total of 793 publications on the use of nerve conduits for peripheral nerve injury repair were retrieved from the Web of Science between 2002–2011. The number of publications gradually increased over the 10-year study period. Articles constituted the main type of publication. The most prolific journals were Biomaterials, Microsurgery, and Journal of Biomedical Materials Research Part A. The National Natural Science Foundation of China supported 27 papers, more than any other funding agency. Of the 793 publications, almost half came from American and Chinese authors and institutions. CONCLUSION: Nerve conduits have been studied extensively for peripheral nerve regeneration; however, many problems remain in this field, which are difficult for researchers to reach a consensus.
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Affiliation(s)
- Jinniang Nan
- Department of General Surgery, Second People's Hospital of Panjin, Panjin 124000, Liaoning Province, China
| | - Xuguang Hu
- Department of General Surgery, Second People's Hospital of Panjin, Panjin 124000, Liaoning Province, China
| | - Hongxiu Li
- Department of General Surgery, Second People's Hospital of Panjin, Panjin 124000, Liaoning Province, China
| | - Xiaonong Zhang
- Department of General Surgery, Second People's Hospital of Panjin, Panjin 124000, Liaoning Province, China
| | - Renjing Piao
- Department of General Surgery, Second People's Hospital of Panjin, Panjin 124000, Liaoning Province, China
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22
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Tan A, Rajadas J, Seifalian AM. Biochemical engineering nerve conduits using peptide amphiphiles. J Control Release 2012; 163:342-52. [PMID: 22910143 DOI: 10.1016/j.jconrel.2012.08.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/05/2012] [Accepted: 08/07/2012] [Indexed: 12/30/2022]
Abstract
Peripheral nerve injury is a debilitating condition. The gold standard for treatment is surgery, requiring an autologous nerve graft. Grafts are harvested from another part of the body (a secondary site) to treat the affected primary area. However, autologous nerve graft harvesting is not without risks, with associated problems including injury to the secondary site. Research into biomaterials has engendered the use of bioartificial nerve conduits as an alternative to autologous nerve grafts. These include synthetic and artificial materials, which can be manufactured into nerve conduits using techniques inspired by nanotechnology. Recent evidence indicates that peptide amphiphiles (PAs) are promising candidates for use as materials for bioengineering nerve conduits. PAs are biocompatible and biodegradable protein-based nanomaterials, capable of self-assembly in aqueous solutions. Their self-assembly system, coupled with their intrinsic capacity for carrying bioactive epitopes for tissue regeneration, form particularly novel attributes for biochemically-engineered materials. Furthermore, PAs can function as biomimetic materials and advanced drug delivery platforms for sustained and controlled release of a plethora of therapeutic agents. Here we review the realm of nerve conduit tissue engineering and the potential for PAs as viable materials in this exciting and rapidly advancing field.
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Affiliation(s)
- Aaron Tan
- Centre for Nanotechnology & Regenerative Medicine, UCL Division of Surgery & Interventional Science, University College London, London, UK
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23
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Muscle recovery after repair of short and long peripheral nerve gaps using fibrin conduits. Neurosci Lett 2011; 500:41-6. [DOI: 10.1016/j.neulet.2011.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 05/18/2011] [Accepted: 06/01/2011] [Indexed: 02/07/2023]
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Bauchet L, Lonjon N, Perrin FE, Gilbert C, Privat A, Fattal C. Strategies for spinal cord repair after injury: a review of the literature and information. Ann Phys Rehabil Med 2011; 52:330-51. [PMID: 19886026 DOI: 10.1016/j.annrmp.2008.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Thanks to the Internet, we can now have access to more information about spinal cord repair. Spinal cord injured (SCI) patients request more information and hospitals offer specific spinal cord repair medical consultations. OBJECTIVE Provide practical and relevant elements to physicians and other healthcare professionals involved in the care of SCI patients in order to provide adequate answers to their questions. METHOD Our literature review was based on English and French publications indexed in PubMed and the main Internet websites dedicated to spinal cord repair. RESULTS A wide array of research possibilities including notions of anatomy, physiology, biology, anatomopathology and spinal cord imaging is available for the global care of the SCI patient. Prevention and repair strategies (regeneration, transplant, stem cells, gene therapy, biomaterials, using sublesional uninjured spinal tissue, electrical stimulation, brain/computer interface, etc.) for the injured spinal cord are under development. It is necessary to detail the studies conducted and define the limits of these new strategies and benchmark them to the realistic medical and rehabilitation care available to these patients. CONCLUSION Research is quickly progressing and clinical trials will be developed in the near future. They will have to answer to strict methodological and ethical guidelines. They will first be designed for a small number of patients. The results will probably be fragmented and progress will be made through different successive steps.
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Affiliation(s)
- L Bauchet
- Centre mutualiste neurologique Propara, 34195 Montpellier, France.
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25
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BD™ PuraMatrix™ peptide hydrogel seeded with Schwann cells for peripheral nerve regeneration. Brain Res Bull 2010; 83:207-13. [PMID: 20633614 DOI: 10.1016/j.brainresbull.2010.07.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/13/2010] [Accepted: 07/02/2010] [Indexed: 01/25/2023]
Abstract
This study investigated the effects of a membrane conduit filled with a synthetic matrix BD™ PuraMatrix™ peptide (BD) hydrogel and cultured Schwann cells on regeneration after peripheral nerve injury in adult rats. After sciatic axotomy, a 10mm gap between the nerve stumps was bridged using ultrafiltration membrane conduits filled with BD hydrogel or BD hydrogel containing Schwann cells. In control experiments, the nerve defect was bridged using either membrane conduits with alginate/fibronectin hydrogel or autologous nerve graft. Axonal regeneration within the conduit was assessed at 3 weeks and regeneration of spinal motoneurons and recovery of muscle weight evaluated at 16 weeks postoperatively. Schwann cells survived in the BD hydrogel both in culture and after transplantation into the nerve defect. Regenerating axons grew significantly longer distances within the conduits filled with BD hydrogel when compared with the alginate/fibronectin hydrogel and alginate/fibronectin with Schwann cells. Addition of Schwann cells to the BD hydrogel considerably increased regeneration distance with axons crossing the injury gap and entering into the distal nerve stump. The conduits with BD hydrogel showed a linear alignment of nerve fibers and Schwann cells. The number of regenerating motoneurons and recovery of the weight of the gastrocnemius muscle was inferior in BD hydrogel and alginate/fibronectin groups compared with nerve grafting. Addition of Schwann cells did not improve regeneration of motoneurons or muscle recovery. The present results suggest that BD hydrogel with Schwann cells could be used within biosynthetic conduits to increase the rate of axonal regeneration across a nerve defect.
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26
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Merolli A, Marceddu S, Rocchi L, Catalano F. In vivo study of ethyl-2-cyanoacrylate applied in direct contact with nerves regenerating in a novel nerve-guide. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2010; 21:1979-1987. [PMID: 20300954 DOI: 10.1007/s10856-010-4036-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2010] [Accepted: 02/22/2010] [Indexed: 05/29/2023]
Abstract
Stitch suture is still the most recommended method to hold a nerve-guide in place but stitch suture is a well known cause of local inflammatory response. Glues of several kinds have been proposed as an alternative but they are not easy to apply in a real surgical setting. In 2006 authors developed a new concept of nerve-guide termed "NeuroBox" which is double-halved, not-degradable and rigid, and allows the use of cyanoacrylic glues. In this study, Authors analyzed histologically the nerve-glue interface. Wistar rats were used as animal model. In group 1, animals were implanted a NeuroBox to promote the regeneration of an experimentally produced 4 mm gap in the sciatic nerve. In group 2, the gap was left without repair ("sham-operated" group). Group 3 was assembled by harvesting 10 contralateral intact nerves to document the normal anatomy. Semi-thin sections for visible light microscopy and ultra-thin sections for Transmission Electron Microscopy were analyzed. Results showed that application of ethyl-2-cyanoacrylate directly to the epineurium produced no significative insult to the underlining nerve fibers nor impaired nerve regeneration. No regeneration occurred in the "sham-operated" group.
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Affiliation(s)
- A Merolli
- Orthopaedics and Hand Surgery Unit, The Catholic University School of Medicine in Rome, Complesso "Columbus", via Moscati 31, 00168 Rome, Italy.
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27
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Biodegradable fibrin conduit promotes long-term regeneration after peripheral nerve injury in adult rats. J Plast Reconstr Aesthet Surg 2009; 63:1893-9. [PMID: 20005193 DOI: 10.1016/j.bjps.2009.11.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 10/28/2009] [Accepted: 11/13/2009] [Indexed: 01/05/2023]
Abstract
Peripheral nerve injuries are often associated with loss of nerve tissue and require autologous nerve grafts to provide a physical substrate for axonal growth. Biosynthetic neural conduits could be an alternative treatment strategy in such injuries. The present study investigates the long-term effects of a tubular fibrin conduit on neuronal regeneration, axonal sprouting and recovery of muscle weight following peripheral nerve injury and repair in adult rats. Sciatic axotomy was performed proximally in the thigh to create a 10-mm gap between the nerve stumps. The injury gap was bridged by using a 14-mm-long fibrin glue conduit, entubulating 2 mm of the nerve stump at each end. A reversed autologous nerve graft was used as a control. The regenerative response from sensory and motor neurones was evaluated following retrograde labelling with Fast Blue fluorescent tracer. In control experiments, at 16 weeks following peripheral nerve grafting, 5184 (±574 standard error of mean (SEM)) sensory dorsal root ganglion neurones and 1001 (±37 SEM) spinal motor neurones regenerated across the distal nerve-graft interface. The fibrin conduit promoted regeneration of 60% of sensory neurones and 52% of motor neurones when compared to the control group. The total number of myelinated axons in the distal nerve stump in the fibrin-conduit group reached 86% of the control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89% of the controls, respectively. The present results suggest that a tubular fibrin conduit can be used to promote neuronal regeneration following peripheral nerve injury.
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Kemp SWP, Syed S, Walsh W, Zochodne DW, Midha R. Collagen nerve conduits promote enhanced axonal regeneration, schwann cell association, and neovascularization compared to silicone conduits. Tissue Eng Part A 2009; 15:1975-88. [PMID: 19196132 DOI: 10.1089/ten.tea.2008.0338] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Peripheral nerve regeneration within guidance conduits involves a critical association between regenerating axons, Schwann cells (SCs), and neovascularization. However, it is currently unknown if there is a greater association between these factors in nonpermeable versus semipermeable nerve guide conduits. We therefore examined this collaboration in both silicone- and collagen-based nerve conduits in both 5- and 10-mm-injury gaps in rat sciatic nerves. Results indicate that collagen conduits promoted enhanced axonal and SC regeneration and association when compared to silicone conduits in the shorter 5-mm-gap model. In addition, collagen tubes displayed enhanced neovascularization over silicone conduits, suggesting that these three factors are intimately related in successful peripheral nerve regeneration. At later time points (1- and 2-month analysis) in a 10-mm-gap model, collagen tubes displayed enhanced axonal regeneration, myelination, and vascularization when compared to silicone-based conduits. Results from these studies suggest that regenerating cables within collagen-based conduits are revascularized earlier and more completely, which in turn enhances peripheral nerve regeneration through these nerve guides as compared to silicone conduits.
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Affiliation(s)
- Stephen W P Kemp
- Department of Clinical Neuroscience, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada.
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Use of Electrical Stimulation at Different Current Levels to Promote Recovery After Peripheral Nerve Injury in Rats. ACTA ACUST UNITED AC 2009; 67:1066-72. [DOI: 10.1097/ta.0b013e318182351a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Bridging nerve gaps with suitable grafts is a major clinical problem. The autologous nerve graft is considered to be the gold standard, providing the best functional results; however, donor site morbidity is still a major disadvantage. Various attempts have been made to overcome the problems of autologous nerve grafts with artificial nerve tubes, which are “ready-to-use” in almost every situation. A wide range of materials have been used in animal models but only few have been applied to date clinically, where biocompatibility is an inevitable prerequisite. This review gives an idea about artificial nerve tubes with special focus on their biocompatibility in animals and humans.
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Affiliation(s)
- Felix Stang
- Department of Plastic, Reconstructive and Hand Surgery, University of Luebeck, 23538 Luebeck, Germany
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-451-5002061; Fax: +49-451-5002190
| | - Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, University of Magdeburg, 39120 Magdeburg, Germany; E-Mail:
| | - Hisham Fansa
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Klinikum Bielefeld-Mitte, 33604 Bielefeld, Germany; E-Mail:
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Chang JY, Ho TY, Lee HC, Lai YL, Lu MC, Yao CH, Chen YS. Highly Permeable Genipin-Cross-linked Gelatin Conduits Enhance Peripheral Nerve Regeneration. Artif Organs 2009; 33:1075-85. [DOI: 10.1111/j.1525-1594.2009.00818.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Kempton LB, Gonzalez MH, Leven RM, Hughes WF, Beddow S, Santhiraj Y, Archibald SJ, El Hassan B, Shott S, Kerns JM. Assessment of Axonal Growth into Collagen Nerve Guides Containing VEGF-Transfected Stem Cells in Matrigel. Anat Rec (Hoboken) 2009; 292:214-24. [DOI: 10.1002/ar.20844] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Merolli A, Rocchi L, Catalano F, Planell J, Engel E, Martinez E, Sbernardori MC, Marceddu S, Tranquilli Leali P. In vivo regeneration of rat sciatic nerve in a double-halved stitch-less guide: A pilot-study. Microsurgery 2009; 29:310-8. [DOI: 10.1002/micr.20622] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Siemionow M, Brzezicki G. Chapter 8: Current techniques and concepts in peripheral nerve repair. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:141-72. [PMID: 19682637 DOI: 10.1016/s0074-7742(09)87008-6] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Despite the progress in understanding the pathophysiology of peripheral nervous system injury and regeneration, as well as advancements in microsurgical techniques, peripheral nerve injuries are still a major challenge for reconstructive surgeons. Thorough knowledge of anatomy, pathophysiology, and surgical reconstruction is a prerequisite of proper peripheral nerve injury management. This chapter reviews the currently available surgical treatment options for different types of nerve injuries in clinical conditions. In overview of direct nerve repair, various end-to-end coaptation techniques and the role of end-to-side repair for proximal nerve injuries is described. When primary repair cannot be performed without undue tension, nerve grafting or tubulization techniques are required. Current gold standard for bridging nerve gaps is nerve autografting. However, disadvantages of this approach, such as donor site morbidity and limited length of available graft material encouraged the search for alternative means of nerve gap reconstruction. Nerve allografting was introduced for repair of extensive nerve injuries. Tubulization techniques with natural or artificial conduits are applicable as an alternative for bridging short nerve defects without the morbidities associated with harvesting of autologous nerve grafts. Achieving better outcomes depends both on the advancements in microsurgical techniques and introduction of molecular biology discoveries into clinical practice. The field of peripheral nerve research is dynamically developing and concentrates on more sophisticated approaches tested at the basic science level. Future directions in peripheral nerve reconstruction including, tolerance induction and minimal immunosuppression for nerve allografting, cell based supportive therapies and bioengineering of nerve conduits are also reviewed in this chapter.
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Affiliation(s)
- Maria Siemionow
- Cleveland Clinic, Department of Plastic Surgery, Cleveland, Ohio 44195, USA
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Ichihara S, Inada Y, Nakamura T. Artificial nerve tubes and their application for repair of peripheral nerve injury: an update of current concepts. Injury 2008; 39 Suppl 4:29-39. [PMID: 18804584 DOI: 10.1016/j.injury.2008.08.029] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Over the last 20 years, an increasing number of research articles have reported on the use of artificial nerve tubes to repair nerve defects. The development of an artificial nerve tube as an alternative to autogenous nerve grafting is currently a focus of interest for peripheral nerve repair. The clinical employment of tubes as an alternative to autogenous nerve grafts is mainly justified by the limited availability of donor tissue for nerve autografts and the related morbidity. Numerous studies indicate that short-distance defects in humans can be successfully treated by implantation of artificial nerve guides. This review provides a brief overview of various preclinical and clinical trials conducted to evaluate the utility of artificial nerve tubes for the regeneration of peripheral nerves. This review is also intended to help update hand surgeons on the rapid advances in tubulization techniques, and to provide them with indications of the various directions toward which future research can proceed. Future studies need to provide us with as much comparative information as possible on the effectiveness of different tubulization techniques, in order to guide the surgeon in choosing the best indications for their optimal clinical employment. Future progress in implant development can be expected from interdisciplinary approaches involving both materials and life sciences, leading to advances in neuro-tissue engineering that will be needed to effectively treat larger nerve defects.
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Affiliation(s)
- Satoshi Ichihara
- Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
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Panseri S, Cunha C, Lowery J, Del Carro U, Taraballi F, Amadio S, Vescovi A, Gelain F. Electrospun micro- and nanofiber tubes for functional nervous regeneration in sciatic nerve transections. BMC Biotechnol 2008; 8:39. [PMID: 18405347 PMCID: PMC2358889 DOI: 10.1186/1472-6750-8-39] [Citation(s) in RCA: 181] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 04/11/2008] [Indexed: 12/22/2022] Open
Abstract
Background Although many nerve prostheses have been proposed in recent years, in the case of consistent loss of nervous tissue peripheral nerve injury is still a traumatic pathology that may impair patient's movements by interrupting his motor-sensory pathways. In the last few decades tissue engineering has opened the door to new approaches;: however most of them make use of rigid channel guides that may cause cell loss due to the lack of physiological local stresses exerted over the nervous tissue during patient's movement. Electrospinning technique makes it possible to spin microfiber and nanofiber flexible tubular scaffolds composed of a number of natural and synthetic components, showing high porosity and remarkable surface/volume ratio. Results In this study we used electrospun tubes made of biodegradable polymers (a blend of PLGA/PCL) to regenerate a 10-mm nerve gap in a rat sciatic nerve in vivo. Experimental groups comprise lesioned animals (control group) and lesioned animals subjected to guide conduits implantated at the severed nerve stumps, where the tubular scaffolds are filled with saline solution. Four months after surgery, sciatic nerves failed to reconnect the two stumps of transected nerves in the control animal group. In most of the treated animals the electrospun tubes induced nervous regeneration and functional reconnection of the two severed sciatic nerve tracts. Myelination and collagen IV deposition have been detected in concurrence with regenerated fibers. No significant inflammatory response has been found. Neural tracers revealed the re-establishment of functional neuronal connections and evoked potential results showed the reinnervation of the target muscles in the majority of the treated animals. Conclusion Corroborating previous works, this study indicates that electrospun tubes, with no additional biological coating or drug loading treatment, are promising scaffolds for functional nervous regeneration. They can be knitted in meshes and various frames depending on the cytoarchitecture of the tissue to be regenerated. The versatility of this technique gives room for further scaffold improvements, like tuning the mechanical properties of the tubular structure or providing biomimetic functionalization. Moreover, these guidance conduits can be loaded with various fillers like collagen, fibrin, or self-assembling peptide gels or loaded with neurotrophic factors and seeded with cells. Electrospun scaffolds can also be synthesized in different micro-architectures to regenerate lesions in other tissues like skin and bone.
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Affiliation(s)
- Silvia Panseri
- Bioscience and Biotechnology Department, University of Milan-Bicocca, Piazza della Scienza 2, Milan, Italy.
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